JP2004327073A - Fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stand-alone fuel cell power generation system with improved power supply stability. <P>SOLUTION: The fuel cell power generation system converts the output power of a fuel cell 2 for generating power by receiving fuel from a fuel supply device 1 into alternating current power by an inverter 5, and supplies the alternating power to a load device X. The system comprises a current regulating means 3 for regulating the current to be taken out from the fuel cell 2; variation detecting means 6, 7 for measuring variations in input power to the invertor 5 and outputting it as measured values; and a control means for synchronously controlling the regulating means 3 and the supply device 1 so as to suppress the variation in the measured values. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel cell power generation system.
[0002]
Problems to be solved by the prior art and the invention
2. Description of the Related Art Among fuel cell power generation systems, there is a stand-alone type system that independently supplies power to a load device without cooperating with a commercial power supply system. In such a stand-alone system, the output power of the fuel cell cannot be controlled in accordance with the demanded power. Therefore, a battery is additionally provided, and the shortage of the output power of the fuel cell with respect to the demanded power is provided by this battery. By making up for this, stable power is supplied to the load devices.
[0003]
That is, the response speed of the fuel supply to the fuel cell is slow with respect to the fluctuation of the demanded power, and the fuel cell reforms the fuel by the reformer to generate power. Is also slow to fluctuations in demand power, and therefore the fuel cell cannot follow steep fluctuations in demand power. Therefore, the stand-alone system employs a configuration in which such a steep change in demand power is compensated for by the output power of the battery.
[0004]
However, in such a stand-alone type system, the output current of the fuel cell fluctuates so as to simply follow the demand power without any control, so that the output current of the fuel cell fluctuates with relatively high responsiveness. Does not match the amount of fuel supply to the fuel cell, which fluctuates slowly, and as a result, the operation of the fuel cell becomes unstable. Therefore, in the conventional stand-alone system, the power supply stability of the entire system is not sufficient. The details of such a stand-alone system are described in, for example, the following known documents.
[0005]
[Patent Document 1]
JP 2002-231289 A
[Patent Document 2]
JP-A-10-284102
The present invention has been made in view of the above problems, and has as its object to improve the power supply stability of a stand-alone fuel cell power generation system.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, as a first means, a fuel cell that receives output of fuel from a fuel supply device and converts the output power of the fuel cell into AC power by an inverter and supplies the AC power to a load device A power generation system, a current adjusting means for adjusting a current taken from a fuel cell, a fluctuation detecting means for measuring a fluctuation of an input power of an inverter and outputting it as a measured value, and a current adjusting means for suppressing a fluctuation of the measured value And a control means for synchronously controlling the fuel supply device and the fuel supply device.
[0009]
As a second means, a fuel supply device, a fuel cell for outputting electric power corresponding to the fuel supplied from the fuel supply device, and an output current of the fuel cell controlled based on a current command and output as a charging current A charger, a battery for charging a current input from the charger, an inverter for converting output power of the battery into AC power and supplying the AC power to a load device, and measuring a change in the input power of the inverter as a measured value. A configuration including a fluctuation detecting means for outputting and a control means for synchronously controlling the charger and the fuel supply device so as to suppress the fluctuation of the measured value is adopted.
[0010]
As a third means, in the first means, the fluctuation detecting means is either one of an ammeter for measuring the current of the input power of the inverter as a current value and a voltmeter for measuring the voltage value of the input power of the inverter or The configuration of both is adopted.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a fuel cell power generation system according to the present invention will be described with reference to the drawings.
[0012]
FIG. 1 is a block diagram showing a functional configuration of the fuel cell power generation system. In this figure, reference numeral 1 denotes a fuel supply device, 2 denotes a fuel cell, 3 denotes a charger (current adjusting means), 4 denotes a battery, 5 denotes an inverter, 6 denotes a DC voltmeter (fluctuation detecting means), and 7 denotes a DC ammeter ( Fluctuation detecting means), 8 is a fuel cell control device (control means), and X is a load device.
[0013]
The fuel supply device 1 supplies the fuel cell 2 with fuel and air in an amount (fuel supply amount) according to a fuel supply command input from the fuel cell control device 8. The fuel cell 2 generates a current corresponding to the fuel supply amount and outputs the current to the charger 3. In general, various types of fuel cells are known, but the fuel cell 2 in the present embodiment is not limited to a specific type. The charger 3 outputs, to the battery 4, a charging current of an amount corresponding to a charging current command input from the fuel cell control device 8 among the currents supplied from the fuel cell 2. The battery 4 stores the charging current input from the charger 3 as DC power in this way, and supplies the DC power to the inverter 5.
[0014]
The inverter 5 converts the DC power supplied from the battery 4 into AC power and supplies the AC power to various load devices X. The DC voltmeter 6 measures a voltage value of the DC power and outputs it to the fuel cell control device 8 as a monitor voltage. The DC ammeter 7 measures a current value of the DC power and outputs the measured current value to the fuel cell control device 8 as a monitor current. The fuel cell control device 8 synchronously controls the fuel supply device 1 and the charger 3 by synchronously generating the fuel supply command and the charging current command based on the monitor voltage and the monitor current. The load device X is not limited to a specific device, but is, for example, a store light, a refrigerator, or various power devices.
[0015]
Next, the operation of the fuel cell power generation system thus configured will be described in detail.
[0016]
In the present fuel cell power generation system, the inverter 5 outputs the AC power of the total load power required by each load device X at a predetermined commercial frequency (50 Hz or 60 Hz) and a predetermined commercial voltage (effective value 100 V). Although it operates, in order to realize such an operation of the inverter 5, it is necessary to always store DC power corresponding to the total load power amount in the battery 4 which is a power supply source of AC power. That is, in order to stably supply power to each load device X, it is necessary to control the current generation amount of the fuel cell 2 that supplies the charging current to the battery 4 according to the DC power output from the battery 4. is there.
[0017]
In response to such a need, the fuel cell control device 8 of the present fuel cell power generation system uses the monitor voltage input from the DC voltmeter 6 and the monitor current input from the DC ammeter 7, that is, from the monitor voltage and the monitor current. A fuel supply command and a charging current command are synchronously generated based on the obtained DC power of the battery 4 to control the fuel supply amount of the fuel supply device 1 according to the fuel supply command, and the charging current of the charger 3 is controlled according to the charging current command. Since the control is performed, that is, the fuel supply device 1 and the charger 3 are synchronously controlled, a current corresponding to the total load power can be generated in the fuel cell 2 and the battery 4 can be charged. Can be supplied to each load device X stably.
[0018]
Here, the fluctuation in the total load power directly appears due to the monitor current. The fluctuation of the monitor voltage is slow relative to the fluctuation of the total load power. Therefore, even if the fuel supply command and the charging current command are generated based only on the monitor current, and the fuel supply device 1 and the charger 3 are controlled based on the generated fuel supply command and charging current command, The AC power according to the load power amount can be supplied to each load device X with sufficient stability. In addition, assuming that the fluctuation of the total load power is slow, that is, when the load fluctuation of each load device X is slow, the fuel supply command and the charging current command are generated based only on the monitor voltage. The fuel supply device 1 and the charger 3 may be controlled based on the fuel supply command and the charging current command generated as described above.
[0019]
Further, as described above, the fuel cell control device 8 controls the fuel supply device 1 and the charger 3 synchronously, that is, when it is necessary to increase the charging current for charging the battery 4, the charging current command for instructing the increase is given. And a fuel supply command for instructing an increase in the fuel supply amount, and controls the fuel supply device 1 and the charger 3 so that the charging current and the fuel supply amount always increase in synchronization with each other. When it is necessary to reduce the charging current for charging the battery, a charging current command for instructing the reduction is generated and a fuel supply command for instructing the reduction of the fuel supply amount is generated. Since the fuel supply device 1 and the charger 3 are controlled to decrease synchronously, the fuel cell 2 receives an amount of fuel supply corresponding to the amount of current required by the charger 3, and therefore the fuel Operating efficiency of the battery 2 can be improved.
[0020]
The present invention is intended to synchronously control a fuel supply device that supplies fuel to a fuel cell and a current adjusting unit that adjusts the output current of the fuel cell. Changes are possible.
[0021]
【The invention's effect】
As described above, according to the present invention, there is provided a fuel cell power generation system that converts output power of a fuel cell that receives fuel supply from a fuel supply device and generates electric power into AC power by an inverter and supplies the AC power to a load device, Current adjusting means for adjusting the current taken out of the fuel cell, fluctuation detecting means for measuring the fluctuation of the input power of the inverter and outputting it as a measured value, and synchronizing the current regulating means and the fuel supply device so as to suppress the fluctuation of the measured value Since the control means is provided, the operation of the fuel cell is stabilized, and the stability of power supply can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a functional configuration of an embodiment of the present invention.
[Explanation of symbols]
1 ... fuel supply device 2 ... fuel cell 3 ... charger (current adjusting means)
4 Battery 5 Inverter 6 DC voltmeter (fluctuation detecting means)
7 DC ammeter (fluctuation detection means)
8. Fuel cell control device (control means)
X: Load equipment

Claims (3)

A fuel cell power generation system that converts output power of a fuel cell that receives fuel supply from a fuel supply device and generates power to AC power by an inverter and supplies the AC power to a load device,
Current adjusting means for adjusting the current taken from the fuel cell;
Fluctuation detection means for measuring the fluctuation of the input power of the inverter and outputting it as a measured value;
A fuel cell power generation system, comprising: a control unit that controls the current control unit and the fuel supply device synchronously so as to suppress the fluctuation of the measured value. A fuel supply device;
A fuel cell that outputs electric power according to the fuel supplied from the fuel supply device,
A charger that controls the output current of the fuel cell based on the current command and outputs the current as a charging current;
A battery for charging a current input from the charger;
An inverter that converts output power of the battery into AC power and supplies the AC power to a load device;
Fluctuation detection means for measuring the fluctuation of the input power of the inverter and outputting it as a measured value;
Control means for synchronously controlling the charger and the fuel supply device so as to suppress the fluctuation of the measured value. 3. The method according to claim 1, wherein the variation detecting means is one or both of an ammeter for measuring a current of the input power of the inverter as a current value and a voltmeter for measuring a voltage value of the input power of the inverter. The fuel cell power generation system as described in the above.

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